Fuel pump



A. C. KORTE FUEL PUMP Original Filed June 30, 1958 3,163,354 FUEL PUMPAlfred C. Korte, Jennings, Mm, assignor to ACE Industries Incorporated,New York, N.Y., a corporation of New Jersey ,7 h Original applicationJune 30, 1958, Ser. No. 745,358- Divided and this application Dec. 21,1961, Ser. No.

4 Claims. ((31. 230-172) This invention relates to vacuum boostersespecially for use in connection with the engine of an automotivevehicle adapted to supplement, when required, the vacuum obtainable fromthe intake manifold of the engine for effective operation ofvacuum-operated automotive accessories, such as windshield wipers, andmore particularly to a booster pump construction for such use.

With the wider, wrap-around Windshields on present automotive vehicles,the blades of the windshield Wipers of the vehicles are more heavilyloaded than heretofore, and require more powerful vacuum motors andhence more powerful boosters for positive continuous wiper action.Booster pumps are conventionally diaphragmtype pumps, but since theeffective area of the diaphragm in such a pump is only a portion of itstotal area, the volumetric efficiency of a diaphragm-type booster pumpis relatively low. Thus, for high capacity, a diaphragmtype booster pumpmust be made of such size as to take up considerable space under thehood of a Vehicle, where space is at a premium.

Accordingly, it is an abject of this invention to provide a booster pumpwhich, while being compact so as not to take up an undue amount of spaceunder the hood of a vehicle, is of relatively high volumetric efliciencyand hence of relatively high capacity as regards a conventionaldiaphragm-type booster pump of comparable size, and which is capable ofdevelopin s'ufiicie'nt vacuum for operation of a vacuum wiper motor toprovide adequate wiper blade activity despite heavy blade loading andrelatively high wiper displacement. In accordance with this object, thepump of this invention is a piston type pump of relatively highvolumetric efiici'ency, and of the doubleacting type forgreatercapacity.

An automotive vehicle is conventionally equipped with a fuel pump,usuually a mechanical fuel pump of the diaphragm type, for pumping fuelto the carburetor for the engine. One type of mechanical fuel pump ofthis class has a housing in which is pivoted a rocker arm for actuatingthe fuel pump diaphragm, this housing being adapted for connection tothe engine in communication with the crankcase of the engine.

A feature of the present invention is that the doubleacting piston typevacuum booster pump is made part of a combined fuel pump and boosterpump unit, utilizing the rocker arm for actuating both the diaphragm ofthe fuel pump and the piston of the booster pump, one object of thisconstruction being economy of manufacture.

Another object of the invention is the provision of a construction suchas above described which provides for a piston and cylinder constructionwhich provides a booster pump which is economical infabrication yetefficient in operation.

A further object of the invention isthe provision of a vacuum circuitincluding the double-acting piston-type vacuum booster pump by means ofwhich the booster pump is maintained inactive when the manifold vacuumduced stroke.

I 3,163,354 Patented Dec. 29, 1984 ice Other objects and features willbe in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

This application is a division of my copending application Serial Number745,358 and filed on June 30, 1958, now abandoned. V

In the accompanying drawings, in which several of various possibleembodiments of the invention are illustrated,

FIGURE 1 is a plan view of a combined fuel umpand booster pump unitincorporating the invention, parts being broken away;

FIGURE 2 is a view in elevation of the FIGURE 1 unit with parts brokenaway and shown in section, also illustrating the vacuum circuit in whichthe booster pump is included; 1 1 h 7 FIGURE 3 is a view in elevation ofFIGURE 2 as viewed from the right, omitting an eccentric shown in FIGURE2; 7

FIGURE 4 is an ideal vertical section,- the upper part thereof being asection on line 4A-4A of FIGURE 1 and the lower part thereof being insection on line 4B}4B of FIGURE 1, the piston of the booster pump beingomitted;

FIGURE 5 is an enlarged fragment of FIGURE 1 illustrating a packing forthe piston of the booster pump;

FIGURE 6 is a view similar to FIGURE 5 illustrating a modification ofthe booster pump piston packing; and,

FIGURE 7 is across section of a double check value included in thevacuum circuit, taken on line 7-'- 7 of FIGURE 2.

' Corresponding reference characters indicate corresponding partsthroughout the several veiws of the draw- Referring to the drawings,there is shown a combination fuel pump and vacuum booster pump unit ofthis im vention, the fuel pump part of the unit being designated 1 andthe booster pump part of the unitbeing designated 3. These units have incommon a rocker arm housing 5 and a rocker arm 7 pivoted at 9 in thehousing. It will be understood that the unit is mounted on an internalcombustion engine as by means of an adaptor 11 with housing 5 incommunication with the crankcase of the engine. Accordingly, housing 5contains oil fumes from the crankcase. On the outer end of the rockerarm is a slidable shoe 13. When the unit is mounted on the engine, thisshoe is engaged by an eccentric 15 on the engine cam shaft 17. A spring19 biases the rocker arm in the direction (counterclockwise as shown inFIGURE 2) to maintain the shoe in engagement with the eccentric.

The fuel pump 1 is a diaphragm type of pump. It may be of any suitableconstruction; for example, it may be of the type shown and described inthe Coffey, United States Patent 2,803,265, issued August 20, 1957. Thediaphragm 2-1 of the fuel pump is mounted at the lower end of a stem 23.The housing 5 includes a downwardly extending enclosure 25 for thediaphragm. A spring 27 in the enclosure biases the diaphragm downward;The stem23 extends slidably through a packing member 29 held at theupper end of enclosure 25 in an opening 31 between the housing 5 andenclosure 25. Spring 27 surrounds the stem; T he latter extendsup intothe inner'end of housing 5 and through a'slot 33 in the inner end of ithe rocker arm 7, and has a head 35 at its upper end. The rockerv arm isengageabl'e with head 35 for lifting the stem 23 to load spring 7' Thebooster pump 3 comprises a cylinder designated in its entirety by therefefence character 37. This cylinder is constituted by anupwardlyextending annular wall 39 which, as shown, is integrally formed on thehousing 5 above the enclosure 25, by a head 41 at the upper end of wall39, and by a bottom end wall or partition 43 also formed as an integralpart of housing 5. Wall 39 defines a pumping chamber 45. This is closedat its upper end by head 41 and at its lower end bythe wall or partition43', the latter dividing the interior of housing 5 and the chamber. Thepartition 43 is formed, with a central bearing portion 47 in which is anopening 49. A piston rod 51 is vertically slidable in opening 49, havinga sufiiciently loose sliding fit in the opening as to provide arestricted passage around the rod through which oil fumes may enter thepumping chamber 45 for lubrication purposes as will be made clear. Thispassage isso restricted, however, as to avoid any substantial airleakage. Rod 51 extends down into the inner end of housing 5, its lowerend being engageable by the inner end of the rocker arm 7. A piston 53is fixed on the upperend of rod 51 in the chamber.

In accordance with this invention and as shown in FIGURES 2 and 5,piston 53 comprises a pair of circular sheet metal plates 55 and 57. Theupper plate 55 is a flat plate having a diameter slightly less than theinside diameter of the annular wall 39. The lower plate 57 has adownwardly extending annular cylindric skirt or flange 59 and a flat rim61 extending out from the edge of the skirt. The outside diameter ofthis rim is slightly less than the inside diameter of wall 39. Thepiston rod has a reduced-diameter upper end portion 63v providing anupwardly facing annular shoulder 65. Seated on this shoulder is a rigidcircular backing plate 67 having a diameter somewhat less than theinside diameter of the skirt 59. Plate 57 is seated on plate 67 with theskirt 59 extending downward around the periphery of plate 67. The skirt59 and rim 61 provide a groove 68 receiving a flat resilient packingring 69, which may be made of a suitable oil-resistant synthetic rubber;

The thickness of the packing ring 69 is somewhat less than'the width ofthe groove 68 (the, height of the skirt 59). Plate 55 is seated on thecentral portion of plate 57 and confines the packing ring in the groove.In the manufacture of pumps of this invention, the packing rings may bemade in the following manner: A relatively thick-walled rubber tubinghaving an inside diameter slightly less than the outside diameter of theskirt 59 and an outside diameter somewhat greater than the insidediameter. of chamber is formed by extrusion. There is no requirement formaintaining precision of either the inside or outside diameter of theextrusion. These diameters need not be uniform throughout the length ofthe; extrusion. A mandrel having a diameter equal to the outsidediameter of skirt 59 is inserted in a lengthof the tubing. Since theinside diameter of the length of tubing is slightly under size asregards the mandrel, the tubing is expanded to some extent. Then thelength of tubing is exteriorly ground or. otherwise machined to bringits outside diameter down to that required for a sliding sealing fit inchamber 45. Then the length of tubing is cut on a lathe into individualrings 69 of the required thickness. The individual rings are thenstripped from the mandrel, and contract radially with the result thatthe inside and outside diameter of each ring is slightly reduced, theinside diameter becoming slightly less than the outside diameter of theskirt 59.

In assembling the piston 53 and piston rod 51, a ring a 69, made asabove described, is applied around the skirt gether. 'The assembly ofthe piston 53 and, piston rod 51 is then inserted in chamber 45. Sincethe ring 69 has been stretched back to the proper dimensions, itsOutside diameter is such as to have a sliding sealing fit in chamber 45,and its inside periphery has a sliding sealing fit against the skirt 59(the bottom of the groove 68). Thus, even though the lathe-cut ringsasremoved from the mandrel may not be uniform in size, due tonon-uniformity of the original tubing which is apt to occur duringextrusion, any ring when applied to skirt 59 has the proper inside andoutside diameters for sealing purposes. With the thickness of rings 69less than the width of groove 68, the ring has axial clearance in thegroove and hence is free to expand axially when radially compressed, andto slide axially to some extent relative to the plates. Being free toexpand axially, the ring readily'adapts itself for sealing against theinside surface of wall 39, with out requiring accurate machining of thelatter. The con struction is also such as to tend to hold the piston rodagainst canting in opening 49 and to tend to minimize heating. Theplates 67, 57 and may be made by stamping operations and do not requireany machining.

As shown in FIGURE 5, the outside edge of ring 69 is unrelieved.However, as shown in FIGURE 6, it may be provided with a groove asindicated at 72 for relief.

The head 41 is constituted by a separate casting fastened to the wall 39as by screws 73. It is formed with an axial recess 75 opening downwardin the direction toward the pumping chamber 45. A coil compressionspring 77 is received in this recess, reacting from the outer (upper)end of the recess against the piston 53 of driving it downward. The headis formed with a tapered axial re-entrant projection 79 extending downin the recess for centering the spring and filling the space within thespring 77 and recess 75 for volumetric eificiency of the pump. Reentrantprojection 79 terminates short of the lower end of the recess 75 toprovide space for the nut 71 when the piston 53 is at the upper end ofits stroke. The head 41 is formed with a vertical dome-shaped inletpassage 81 and a vertical dome-shaped outlet passage 83 located radiallyoutward of the recess 75 and diametrically 0pposite one another. Aninlet nipple 85 extends up from the head in communication with the inletpassage 81 and an outlet nipple 87 extends up from the head incommunication with'the outlet passage 83. The inlet passage S1 isprovided with a check valve 89 adapted to open in the direction towardthe pumping chamber 45 (downward) and the outlet passage 83 is providedwith a check valve 91 adapted to open'in the direction away from thepumping chamber (upward).

The partition 43 is formed with a vertical inlet passage 93 (see FIGURE,4) and a vertical outlet passage 95 (see FIGURE 2) located radiallyoutward of. the central piston rod bearing portion 47. The outletpassage 95 is generally directly below the outlet passage 83 in the head41, and opens into the inner end of rocker arm housing 5. The inletpassage 93, instead of being diametrically opposite the outlet passage95, is angularly offset from the radial plane of passage 81 as appearsin FIGURE 1;

.FIGURE 4, for convenience,.is drawn with theparts ap pearing as if theywere turned to bring passages 81 and 93 into the same plane. .The head41 has an inclined Jzontal bore 101 is. plugged as indicated at 103mFIG- URE 4. Bores 101, 99 and 97 provide a passage interconnecting theupper and lower inlet passages 81 and 93.

The lower inlet passage 93 is provided with a check valve vided with acheck valve 107 adapted to open. in the direction away from the pumping.chamber (downward toward the interior of housing 5)..

The check valves 89, 9'1, 105,. and 107, as shown,.are all identical.Each comprises a circular. valve seat 109 having a centralhole 111 and aseries of ports 113, such as arcuate slots, around the hole 111..Press-fitted in the hole 111 is a hollow stem 115' closed' as indicatedat 11-7 at its end in the hole, and having its other end a mushroom headconstituting a spring seat 1519. A ring-shaped disk valve member 121',which may be made of a suitable oil-resistant synthetic rubber forcushioned sealing, is slidable on the stem 1'15; and is biased towardengagement' with the valve-seat by a coil compression spring 123surrounding the stern reacting from the seat 119-. As to each of thefour check valves, the valve seat 1-09'is pressfitted and positionedhorizontally in the respective pas.- s'ages 81, S3, 93, 95; with thedisk valve member 121 and stem 11 5' on the appropriate side for inwardor outward opening of thevalve member, asthe case may be. Thus, thestems 11-5 of the valve 105 for inlet passage 93 and the valve 91 foroutlet passage 83 extend upward, and the stems 115 of the valve 107 foroutlet passage 95 and the valve 89 for inlet passage 81 extend downward.

The booster pump 3 is adapted to be connected inseries-parallelrelationwith a vacuum-operated accessory, such as awindshield wiper motor, and the intake manifold of the engine in themanner shownin FIGURE 2, with a double check valve such as indicated at125 in FIGURE 2 and detailed in FIGURE 7 in' the circuit. As shown inFIGURE 7, this double check valve comprises a cupshaped body 127 dividedinto two chambers 129 and 131 by a partition 133 and closed by ahead135. The head 135 has a passage 137 and ports 139 and 141 providing forcommunication between passage 137 and chambers 129 and 131. It also hasnipples 143 and 145, nipple 143 being for connection of a lineto thewiper motor, the other nipple 145 being for connection of a line toanother vacuum-operated accessory if desired. Nipple 145 in thisinstance is shown as capped. The head 135 is formed with check valveseats 147 and 149 around ports 139 and 141 engageable by opposite endportions of a rubber flapper valve member 151. Springs 153 and 155 areprovided in chambers 129 and 131 engageable with the end portions ofmember 151 to bias them toward engagement with the seats 147 and 149.The body has lateral nipples 157 and 159 providing for connection oflines to chambers 129 and 131.

As illustrated in FIGURE 2, a line 161 interconnects the nipple 87 ofthe booster pump 3 and the nipple 159 of the double check valve 125 andthe intake manifold of the engine, a fitting 163 being provided for thelatter purpose. A line 165 interconnects the nipple 85 of the boosterpump and the nipple 157 of the double check valve. A line 167 connectsthe nipple 143 of the double check valve to the windshield wiper motor(not shown). It Will be understood that line 167 has a conventionalWiper motor control valve therein.

Operation is as follows:

Assuming that the windshield wiper motor is in operation, the boosterpump 3 will either be in operation or out of operation, depending uponthe level of manifold vacuum. The manifold vacuum is transmitted to thespace in the booster pump above the piston 53 via the portion of theline 161 between the fitting 163 and the nipple 87. Assuming that thelevel of manifold vacuum is such that the pressure differential on thebooster pump piston 53 is equal to or above that required to overcomethe force of the piston-biasing spring 77, the piston 53 will remain atthe upper end of its stroke. Under these circumstances, a vacuum isdrawn in the wiper motor throughline 167, passage 137 in the head ofvalve 125, port 141 (the flapper valve member 151 opening in thedirection away from the wiper motor and away from seat 149), chamber131, and line 161. The booster pump remains inactive, rocker arm 7simply idling as regards the piston rod 51, the inner 5. end.- of therocker arm moving. away from the lower end of rod 51 on. downwardmovement of the inner end. of the rocker arm as illustrated. bythedotted lines position. of the rocker arm. in FIGURE 2.

When the manifold. vacuum falls below the level. re.- quired to holdrthepiston. 53: at the upper limit of'its stroke; the booster pump becomes.active, spring 77 acting to drivethe piston downward and rocker arm.Tacting to drive it back upward to. the upper. end of its stroke. Thelength of the stroke varies in accordance with the level of; vacuum.Upondownward movement of the piston, valves 89 and 197 open, and valves91 and 105. close. Thus, the piston 53 acts to draw additional vacuumfor operating the wiper motor. via. line 167, passage 137, port 139 (theflappervalve member 1 51 opening. in the direction away from the wipermotor and awayfrom the seat 147), chamber 129,. line 165,. and inletpassage 81. The space below the piston 53 isvented to the interior ofthe rocker armhousing 5 via passage. 95. Upon upward: movement of thepiston; valves 89 and. 107 close, and valves 91 and 105 open. The pistonthereupon acts to draw additional. vacuum for operating the wiper motorvia line 167, passage 137,, port 139,, chamber 129, line 165,. inletpassage 81, passage 97, 99, 101 and inlet passage 93. The space abovethe piston 53 is vented via passage 83 and the portion of line'16-1connecting nipple 87 and the fitting 163. Flapper valve member 151closes on seat 149 toblock off line 161 from passage 137 and prevent airfrom being vented intopassage 137' which would otherwise reduce thevacuum supplied to the wiper motor.

With the rocker arm housing 5 in communication with the crankcase of theengine, and with piston rod 51 having the stated loose fit in bearing47, oil fumes from housing 5 may enter the space in chamber 45 below thepiston 53 and condense upon the interior surface of wall 39 forlubrication purposes. Any excess of oil is forced out of the chamber 45through passage upon downward strokes of the piston (valve 1107 openingon downward strokes of the piston). Air forced out of the chamber 45through passage 95 upon downward strokes of the piston passes into thehousing 5 and thence to the crankcase to tend to augment ventilation ofthe crankcase.

In actual operation of the booster pump on an engine, due to normalfrequent fluctuations in manifold'vacuum, the length of stroke of thepiston 53 fluctuates. Whatever the length of stroke, however, the upperlimit of the stroke is the same. Thus, even though the piston shouldoperate through a full stroke for an interval and wipe the interiofsurface of wall 39 clean, the stroke will shortly be lessened, so thatat least some of the wiped-clean area of the interior surface of wall 39will again receive a film of oil for adequate lubrication.

On strokes of the piston 53 and piston rod 51 shorter than the throw ofthe inner end of rocker arm 7, the inner end of the rocker arm movesaway from the lower 'end of the piston rod in completing its downwardmovement, then on the ensuing upward movement of the inner end of therocker arm, it bumps the lower end of the piston rod and drives thelatter upward. Since the thickness of piston ring 69 is less than thewidth of the groove 68, the ring is adapted in effect to float relativeto the piston. Thus, on a downstroke of the piston from the positionshown in FIGURE 2, the piston tends to move down relative to the ringand then the margin of upper plate 55 engages the ring to drive the ringdown. On an upstroke of the piston the action is reversed. On very shortstrokes of the piston, less than the clearance of ring 69 in groove.

68, the ring may not move at all, the piston idling downward and upwardwithin the ring. This action tends to avoid such stressing of the ringas would tend to make it become heated.

When the wiper is not operating, the booster pump 3 remains on a standbybasis, the piston 53 idling at a considerably reduced stroke.

7 The booster pump 3 is of relatively high volumetric efficiency, therebeing a minimum of clearance volume in the pump cylinder at the ends ofthe stroke of the piston 53. Being volumetrically efficient anddouble-acting, the pump may be made of relatively small size forrelatively high capacity so as to provide ample auxiliary vacuum to thewiper motor whenever required.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous' results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

I claim:

1. In a booster pump, the combination comprising a cylinder, a pistonwithin saidcylinder, said piston being formed of a pair of circularplates secured in faceto face relation, one of said plates having acylindrical flange and a rim extending radially from the flange, theother plate having a radiallyextending rim spaced from the firstmentioned rim and defining a ring groove with the flange and rim of saidone plate, and a piston ring of elastic material'coaxially received insaid ring groove, said piston ring having a sliding fit at its innerperiphery on said cylindrical flange and extending at its outerperiphery beyond said spaced rims to form an effective seal with thecylinder walland with the surface of said cylindrical flange, saidpiston ring having an axial height less than the spacing between saidrims so that said piston ring may move loosely 'therebetw een.

2. .An assembly comprising a cylinder, a piston mounted within thecylinder for back and forth movement and formed of a pair of'sheet metalplates'securedtogether, one of said plates'having a cylindrical flangeand a rim extending radially from the flange, the other plate having aradially extending rim spaced from the first mentioned rim and defininga ring groove with the flange and rim of said one plate, and a resilientpiston ring fitting within the ring groove, said piston ring having asliding fit at its inner periphery on said cylindrical flange andextending at its outer periphery beyond said spaced rims to form a sealwith the cylinder wall and with the surface of the cylindrical flange,said piston ring having an axial height less than the spacing betweensaid rims so that the piston ring may move loosely .therebetween.

3. An assembly as set forth in claim 2 wherein said piston ring isgenerallyrectangular in cross section.

4. An assembly as set forth in claim 2 wherein said piston ring is of agenerally rectangular cross section and has an outwardly facing annulargroove along its outer circumference thereby to relieve the outersurface of the ring adjacent the cylinder wall.

References Cited in the file of this patent UNITED STATES PATENTS 75,927King Mar. 24, 1868 2,002,318 Hueber et al May 21, 1935 2,444,119 Thornet a1. June 29, 1948 2,539,896 Dalrymple Jan. 30, 1951 2,893,795 DoolingJuly 7, 1959

1. IN A BOOSTER PUMP, THE COMBINATION COMPRISING A CYLINDER, A PISTONWITHIN SAID CYLINDER, SAID PISTON BEING FORMED OF A PAIR OF CIRCULARPLATES SECURED IN FACE-TOFACE RELATION, ONE OF SAID PLATES HAVING ACYLINDRICAL FLANGE AND A RIM EXTENDING RADIALLY FROM THE FLANGE, THEOTHER PLATE HAVING A RADIALLY EXTENDING RIM SPACED FROM THE FIRSTMENTIONED RIM AND DEFINING A RING GROOVE WITH THE FLANGE AND RIM OF SAIDONE PLATE, AND A PISTON RING OF ELASTIC MATERIAL COAXIALLY RECEIVED INSAID RING GROOVE, SAID PISTON RING HAVING A SLIDING FIT AT ITS INNERPERIPHERY ON SAID CYLINDRICAL FLANGE AND EXTENDING AT ITS OUTERPERIPHERY BEYOND SAID SPACED RIMS TO FORM AN EFFECTIVE SEAL WITH THECYLINDER WALL AND WITH THE SURFACE OF SAID CYLINDRICAL FLANGE, SAIDPISTON RING HAVING AN AXIAL HEIGHT LESS THAN THE SPACING BETWEEN SAIDRIMS SO THAT SAID PISTON RING MAY MOVE LOOSELY THEREBETWEEN.